Genetic Control of Function and Inheritance Flashcards Preview

Transcription

-rewriting in the same language-Genes as nucleic acid chains in DNA double helixes within nucleus.-Transcribed into nucleic acids in the form of messenger (m)RNA.-Need to transcribe it into an RNA that can leave the nucleus and then this can be read and translated in the cytoplasm in order to form the amino acid chain of a protein-DNA strand unzipped by helicase enzymes-One of two strands serves as template (or sense strand, and the other is the nonsense strand which is the complementary strand)

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Translation

-rewriting in different language-Synthesis of protein chains from mRNA instructions.-Going from nucleic acids to amino acids-Final mRNA sequence an exact copy of DNA template without introns-Therefore, it is an exact copy of JUST the exons --> Exons = EXPRESSED portion of DNA-Ribosomal RNA on ribosome participates in the assembly of amino acids from mRNA code

how is RNA different than DNA

gene expression

-Refers to activity of genes-Induction refers to processes increasing expression, as by an exogenous agent-Repression is prevention of expression-Operons control expression as promoter sites and structural genes

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mutation

-An accident of DNA duplication process-Only mutations of germ cell DNA can be heritable-Many somatic mutations fatal to embryo -There are failures that are more minor that don’t cause demise of the embryo and are more common than the catastrophic failures

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chromosomes

-23 pairs of matched DNA strands, one from each parent-Wrapped up and coiled on histones to form chromatin within the chromosome

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meiosis vs mitosis

genotype vs phenotype

-Genotype – gene structure-Phenotype – gene expression, recognizable traits-Phenotypes are specific but may have more than one genotype associated with it-Therefore, carriers of genetic mutations may not all express their traits to the same degree

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penetrance

-ability of gene to express itself-Most human traits and diseases exhibit polygenic inheritance (not as simple as mendelian genetics with the peas and the flowers

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complimentary genes

each gene mutually dependent on the other

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collaborative genes

two genes together produce phenotype neither would produce alone

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genomic imprinting

-Phenomenon in which one parental genome exhibits more influence over offspring than the other-Ovarian teratomas of maternal while hydatidiform moles of paternal lineage

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linkage

-Genes residing in proximity to each other on a chromosome will tend to travel together without being split by crossing over events-Ex: Color blindness with hemophilia A